Obesity — Is it all bad?

It has been said that the major health epidemic of the 21st-century is diabesity. This is the combination of either predisposition to, or frank, diabetes along with being significantly overweight. Some may argue that the current pandemic of COVID-19 will always be seen as the major epidemic of the early 21st Century. But, when you consider the strong link between diabesity, which accounts for 70% of cardiovascular disease and the fact that we are now seeing 18 million deaths per year around the world from cardiovascular disease, I believe diabesity easily trumps COVID-19 as our major health concern.

A number of studies over the past decade have suggested better mortality rates in people over the age of 50 carrying a bit of extra weight. For most of us in the health industry and the general public, this appears counterintuitive.

Let’s examine some of the evidence. There have been a variety of studies, mainly meta-analyses, which have suggested an inverse link between body weight and health. 40 cohort studies of just over 250,000 participants demonstrated a 13% reduction in all cause death & a 12% reduction in cardiovascular death in overweight patients i.e. Body Mass Index (Weight/ Height in m2) BMI between 25 to 30. There were no differences in the death rates between normal weight people (BMI 20 to 25) and Grade 1 obese people (BMI 30 to 35). In this particular study, however, once the BMI rose above 35, there was an 88% increase in death risk.

A very large meta-analysis of 2.9 million people from 97 trials showed a 6% reduction in death in overweight people when compared with normal weight and Grade 1 obesity.

The benefits are even more striking in hypertensive patients, with a reduction in death, heart attack, stroke of 23% in overweight patients and strangely a 32% reduction in those with Grade 1 obesity and a 24% reduction in those with higher grades of obesity compared with people who are normal weight.

Another study from Holland followed patients for seven years after coronary stenting and demonstrated those who had a BMI between 27.5 up to 30 had a 41% reduction in death.

The benefits of being overweight are also demonstrated for people with heart failure, peripheral arterial disease, stroke, previous history of thrombo-embolism, post coronary bypass grafting, atrial fibrillation, death rates in intensive care, general surgery, type II diabetes, chronic obstructive pulmonary disease, haemodialysis, critically ill patients and those with osteoporosis.

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Photo by i yunmai on Unsplash

This has been coined the obesity paradox. This is where people who are in the overweight or obese range for Body Mass Index (Weight/ Height in m2) BMI, appear to fare better when they develop an illness. A recent trial was published in the European Heart Journal (2020–41, pages 2668–2677) the ORIGIN trial followed just over 12,500 patients, average age 64, 35% female, for over six years with establish risk factors for heart disease, diabetes or prediabetes. They split these patients into 6 BMI groups, less than 22, 22 to 25, 25 to 30, 30 to 35, 35 to 40 and greater than 40. The trial basically found that those who are in the overweight or with grade one Obesity group (25 to 30, 30 to 35 BMI) had a 20% reduction in total deaths compared with those in the lower weight ranges. Those with a lower body weight had a 28% increase in death and a 34% increase in cardiovascular mortality. Even more strange those who lost weight over the study period had a 32% increase in all cause death and an 18% increase in cardiovascular death. Those who gained weight demonstrated no increased death risk.

This all sounds bizarrely counterintuitive but is highly consistent with evidence from a number of other trials including a trial titled LOOKAHEAD and also the Diabetes Care in General Practice trial.

I would like to make some key points here to explain why these results are in such a contrast to the general health advice given by almost all doctors and other health professionals. Firstly, these trials assessed people with either established disease or those with very high risk of developing some form of cardiovascular disease. Also, the average age of the people in the trials mentioned were well over 50 where our metabolism is established and very ingrained. For those who find it easy to lose weight over the age of 50, either intentionally or unintentionally they are certainly outside the norm and it may be that there is some metabolic aberration which predisposes them to more severe disease.

Carrying a modest amount of extra weight around the belly over the age of 50 may be protective because of the salient fact that in a healthy person the covering of every cell, known as the membrane, is 75% fat. This protects us from outside toxins entering our cells. If we do not have a reasonable fatty layer over the age of 50, which is the usual time when our modern killers start to manifest such as cardiovascular disease and cancer, the extra toxins floating around our system can easily cross the “not so fatty membranes of thin people” and contribute to an increased risk for disease.

I have seen in a number of occasions people who embark on some of these radical diets such as the Keto diet, the Paleo diet, the 5:2 diet and even veganism over the age of 50, rapidly lose weight. That spare tire around your belly is not just an ugly lump of lard but also a toxic reservoir that has held onto many inert chemicals over the years. If you lose the fat rapidly these chemicals may pour into your central circulation and may cause trouble. I’ve seen a handful of people over time who had a heart attack or a stroke during the acute weight loss phase of one of these fad diets.

I am still a great believer in people trying to keep their weight down but, just like an archaeological dig, I would prefer this to be done slowly and carefully to allow your metabolism to adjust. If you are carrying a little bit of extra weight, putting you in the 25 to 30 BMI category, rather than agonising over weight loss I would prefer you to focus more on eating healthy food and keep up a regular exercise habit. The combination of a Mediterranean style diet and 3 to 5 hours of moderate exercise per week, with or without significant weight loss, has proven health benefits.

Doctors are always encouraging their patients to lose weight and the reality is that most people are spectacularly unsuccessful in doing so. Although it is my strong belief that it is important for us to keep our weight down to healthy levels, it certainly appears that there is a significant difference between a healthy weight before the age of 50 and over the age of 50.

As anyone over the age of 50 reading this article will fully appreciate that once your hormones go south, whether you’re male or female, it is much more difficult to keep the fat down, especially off your belly. It may well be that obese patients with more severe abdominal obesity and visceral fat died earlier and therefore skewed the data compared with those with less risky lower body obesity. Interestingly, the accumulation of visceral fat is much greater in age group 35 to 45 with an average 52% increase, compared with 55 to 65 with only 7% and for those older than 65, 11%.

So, are there any adequate explanations for this so-called obesity paradox? The first and rather obvious explanation is what we call reverse causality. It is a well-established fact that the sicker patients tend to lose more weight than those who have mild disease. Thus, it is not the obesity that is protecting people rather the loss of weight occurring as a consequence of a more severe illness. Secondly, those people who are carrying less weight with established illnesses such as cardiovascular disease, cancer, osteoporosis and type II diabetes, tend to have a stronger genetic predisposition to the disease. Could it be, therefore, the more genetic an illness, the more seriously it affects the body compared with lifestyle associated disease, which tends to be associated with obesity?

Another explanation is that smokers tend to be thinner than non-smokers but also suffer more serious diseases.

In the specific case of chronic kidney disease this is a chronic inflammatory state and also associated with protein energy wasting. There is a paradoxical association between traditional risk factors & cardiovascular disease in this setting and the weight loss itself may be a marker of more severe disease.

Also, BMI is not as good a marker for abdominal fat as waist circumference and it may be that those with the higher BMI have a larger muscle mass, which is felt to be protective. Also, there is the consideration of being fat but fit which may include better cardiovascular and muscle strength.

It is my strong belief that we should all try and maintain a healthy body weight but over the age of 50, I would suggest you should be aiming for a BMI between 25 to 30 with the waist circumference around 90 to 95 for a male and 75 to 80 for a female. I heard an interesting concept the other day that your waist circumference should be less than half your height.

I advise all my patients beyond the age of 50 to focus more on healthy eating which is basically to eat less and eat more naturally, along with maintaining 3 to 5 hours of testing exercise per week which should include two thirds cardio and a third resistance training. This is much better for your health than obsessing about weight.

Regardless, there is certainly no strong science that once you are over the age of 50 being thin or possibly even more concerning trying to lose too much weight is of any major health benefit. Focusing on eating high-quality food and regular exercise is clearly much better for you and should be one of our major health goals.

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Dr Walker is an expert in the field of preventative cardiology and has published seven books. He gives lectures nationally and internationally.

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